In stockpot over medium-high heat, heat oil. Add onion, celery, bell pepper and garlic. Sauté until onion is translucent 3 to 5 minutes.
Add cumin, chili powder, oregano and black pepper. Sauté 2 to 3 minutes.
Add broth, 1/2 cup of Marinara Sauce and rice. Stir. Bring to a boil. Reduce heat. Cover. Simmer until rice is tender and liquid is absorbed, 20 to 25 minutes. Stir in beans.
Preheat convection oven to 300 F.
Fill each pepper half with filling. Top each with 1/4 cup of Marinara Sauce.
Bake until internal temperature reaches 160 F, 30 to 35 minutes.